Band-limited digital pre-distortion (DPD) expansion estimation and curve adjustment

1. A method comprising:

applying during processing of an input signal, pre-distortion adjustment;

estimating expansion introduced as result of applying the pre-distortion adjustment, wherein estimating the expansion comprises using band-limited expansion estimation, the band-limited expansion estimation comprising:

extracting a non-linear response based on observing a transmit/receive (Tx/Rx) band-limited signal and a training sequence; and

determining an amount of expansion based on the extracted non-linear response;

generating expansion adjustment based on the estimated expansion; and

applying the expansion adjustment in a feedback manner during subsequent processing operations.

2. The method of claim 1 , further comprising applying one or more additional adjustments for handling the estimated expansion and/or to account for applying the expansion adjustments.

3. The method of claim 2 , wherein the one or more additional adjustments comprise at least one of gain adjustment and attenuation adjustment.

4. The method of claim 1 , wherein estimating the expansion comprises:

sampling a gain curve; and

estimating the expansion based on an assessment of positioning of sample points below or above the gain curve.

5. The method of claim 1 , further comprising modifying the pre-distortion adjustment based on feedback received from a receiver-side.

6. The method of claim 5 , further comprising modifying the pre-distortion adjustment by adjusting, based on the feedback received from the receiver-side, pre-distortion curves used when applying pre-distortion.

7. A system comprising:

a transmitter comprising one or more circuits that are configured to:

apply during processing of an input signal, pre-distortion adjustment;

estimate expansion introduced as result of applying the pre-distortion adjustment, wherein estimating the expansion comprises use of band-limited expansion estimation, the one or more circuits being configured to, when using the band-limited expansion estimation:

extract a non-linear response based on observing transmit/receive (Tx/Rx) band-limited signal and a training sequence; and

determine an amount of expansion based on the extracted non-linear response;

generate expansion adjustment based on the estimated expansion; and

apply the expansion adjustment in a feedback manner during subsequent processing operations.

8. The system of claim 7 , wherein the one or more circuits are further configured to apply one or more additional adjustments for handling the estimated expansion and/or to account for applying the expansion adjustments.

9. The system of claim 8 , wherein the one or more additional adjustments comprise one or both of gain adjustment and attenuation adjustment.

10. The system of claim 7 , wherein the one or more circuits are further configured to, when estimating the expansion:

sample a gain curve; and

estimate expansion based on an assessment of positioning of sample points below or above the gain curve.

11. The system of claim 7 , wherein the one or more circuits are further configured to modify the pre-distortion adjustment based on feedback received from a receiver-side.

12. The system of claim 11 , wherein the one or more circuits are further configured to modify the pre-distortion adjustment by adjusting, based on the feedback received from the receiver-side, pre-distortion curves used when applying pre-distortion.

13. A system comprising:

a pre-distortion circuit configured to apply pre-distortion adjustments during processing of signals for transmission; and

a controller circuit for controlling the pre-distortion adjustments applied via the pre-distortion circuit, wherein the controller circuit is configured to:

estimate expansion introduced as result of applying the pre-distortion adjustments, wherein the controller circuit is further configured to, when estimating the expansion:

extract a non-linear response based on observing a band-limited signal and a training sequence; and

determine an amount of expansion based on the extracted non-linear response; and

generate one or more adjustments based on the estimated expansion.

14. The system of claim 13 , wherein the controller circuit is further configured to:

sample a gain curve; and

estimate the expansion based on an assessment of positioning of sample points below or above the gain curve.

15. The system of claim 13 , wherein the controller circuit is further configured to modify the pre-distortion adjustments based on feedback received from a receiver-side.